Greater North Sea Ecoregion

Pressure: Substrate loss and smothering

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​​​​​Substrate loss​​​​​

Extensive lengths of coastline in the North Sea are protected against erosion by coastal defence structures. The almost unbroken line of coastal defence schemes protecting the southern coast of the North Sea has caused extensive fragmentation and loss of habitats. Since 1998, OSPAR countries have reported on the reclamation of around 145 hectares from the sea and coastal wetlands, with the majority of this activity in the Greater North Sea. The largest land reclamation in Europe, Maasvlakte 2, is in Rotterdam port. However, both UK and Dutch authorities are also allowing sea re-encroachment in the southern North Sea as part of flood defences, creating more coastal wetlands. One scheme alone in England has re-flooded some 600 hectares.

Many permanent or semi-permanent structures have been placed offshore in the North Sea, most associated with oil and gas production. Offshore wind farm development has started in the last decade with greater development planned for areas further offshore.

Smothering

Dredging and dumping operations and techniques have not changed recently. The total annual amounts dumped at sea have varied between 80 and 130 million tonnes (dry weight); much of this activity is associated with port expansion and deepening of navigation channels. In 2005, there were around 350 dumpsites in the OSPAR area. About 90% of all sediments dumped each year are dredged and dumped in the southern North Sea. This is largely from maintaining navigation channels to major seaports such as Hull, Antwerp, Rotterdam, Hamburg, and Esbjerg. Cable laying activities have increased (and are projected to continue to increase) proportionate to current plans for offshore wind farm development. Ship traffic and vessel size are predicted to increase from the present until 2020, which will increase the need to maintain (and possibly deepen) navigation channels.